The present invention relates generally to motorized dental handpieces and more particularly to electrically driven handpieces. Hitherto, motorized dental handpieces for the finishing or abrasion of teeth and associated material by means of a rotatable cutting tool, abrasive disk, rubber caps, etc. have conventionally been composed of a body, a central drive gear, a head, a bearing, a head gear shaft, a drivable head gear, a head cap and a flange. The head gear shaft mounted at the head end portion of the handpiece, the head gear, the head cap and the flange have conventionally been constructed so as to be integral with one another by being press-fit into an independent part which is incapable of being disassembled.
Therefore, it was necessary to replace the whole integrated part when only the seal ring, for example, becomes worn and requires replacement.
The present invention provides a handpiece which enables disassembly of the parts mounted at the head end portion of the handpiece, and also provides a complete water proof and dust proof structure in the gap between the head cap and the flange.